1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967
//! Resolves conditional compilation for [`features` section] in the manifest.
//!
//! This is a [new feature resolver] that runs independently of the main
//! dependency resolver. It has several options which can enable new feature
//! resolution behavior.
//!
//! One of its key characteristics is that it can avoid unifying features for
//! shared dependencies in some situations. See [`FeatureOpts`] for the
//! different behaviors that can be enabled. If no extra options are enabled,
//! then it should behave exactly the same as the dependency resolver's
//! feature resolution.
//!
//! The preferred way to engage this new resolver is via [`resolve_ws_with_opts`].
//!
//! This does not *replace* feature resolution in the dependency resolver, but
//! instead acts as a second pass which can *narrow* the features selected in
//! the dependency resolver. The dependency resolver still needs to do its own
//! feature resolution in order to avoid selecting optional dependencies that
//! are never enabled. The dependency resolver could, in theory, just assume
//! all optional dependencies on all packages are enabled (and remove all
//! knowledge of features), but that could introduce new requirements that
//! might change old behavior or cause conflicts. Maybe some day in the future
//! we could experiment with that, but it seems unlikely to work or be all
//! that helpful.
//!
//! ## Assumptions
//!
//! There are many assumptions made about the dependency resolver:
//!
//! * Assumes feature validation has already been done during the construction
//! of feature maps, so the feature resolver doesn't do that validation at all.
//! * Assumes `dev-dependencies` within a dependency have been removed
//! in the given [`Resolve`].
//!
//! There are probably other assumptions that I am forgetting.
//!
//! [`features` section]: https://doc.rust-lang.org/nightly/cargo/reference/features.html
//! [new feature resolver]: https://doc.rust-lang.org/nightly/cargo/reference/resolver.html#feature-resolver-version-2
//! [`resolve_ws_with_opts`]: crate::ops::resolve_ws_with_opts
use crate::core::compiler::{CompileKind, CompileTarget, RustcTargetData};
use crate::core::dependency::{ArtifactTarget, DepKind, Dependency};
use crate::core::resolver::types::FeaturesSet;
use crate::core::resolver::{Resolve, ResolveBehavior};
use crate::core::{FeatureValue, PackageId, PackageIdSpec, PackageSet, Workspace};
use crate::util::interning::InternedString;
use crate::util::CargoResult;
use anyhow::{bail, Context};
use itertools::Itertools;
use std::collections::{BTreeMap, BTreeSet, HashMap, HashSet};
use std::rc::Rc;
/// The key used in various places to store features for a particular dependency.
/// The actual discrimination happens with the [`FeaturesFor`] type.
type PackageFeaturesKey = (PackageId, FeaturesFor);
/// Map of activated features.
type ActivateMap = HashMap<PackageFeaturesKey, BTreeSet<InternedString>>;
/// Set of all activated features for all packages in the resolve graph.
pub struct ResolvedFeatures {
activated_features: ActivateMap,
/// Optional dependencies that should be built.
///
/// The value is the `name_in_toml` of the dependencies.
activated_dependencies: ActivateMap,
opts: FeatureOpts,
}
/// Options for how the feature resolver works.
#[derive(Default)]
pub struct FeatureOpts {
/// Build deps and proc-macros will not share features with other dep kinds,
/// and so won't artifact targets.
/// In other terms, if true, features associated with certain kinds of dependencies
/// will only be unified together.
/// If false, there is only one namespace for features, unifying all features across
/// all dependencies, no matter what kind.
decouple_host_deps: bool,
/// Dev dep features will not be activated unless needed.
decouple_dev_deps: bool,
/// Targets that are not in use will not activate features.
ignore_inactive_targets: bool,
/// If enabled, compare against old resolver (for testing).
compare: bool,
}
/// Flag to indicate if Cargo is building *any* dev units (tests, examples, etc.).
///
/// This disables decoupling of dev dependencies. It may be possible to relax
/// this in the future, but it will require significant changes to how unit
/// dependencies are computed, and can result in longer build times with
/// `cargo test` because the lib may need to be built 3 times instead of
/// twice.
#[derive(Copy, Clone, PartialEq)]
pub enum HasDevUnits {
Yes,
No,
}
/// Flag to indicate that target-specific filtering should be disabled.
#[derive(Copy, Clone, PartialEq)]
pub enum ForceAllTargets {
Yes,
No,
}
/// Flag to indicate if features are requested for a certain type of dependency.
///
/// This is primarily used for constructing a [`PackageFeaturesKey`] to decouple
/// activated features of the same package with different types of dependency.
#[derive(Default, Copy, Clone, Debug, PartialEq, Eq, Ord, PartialOrd, Hash)]
pub enum FeaturesFor {
/// Normal or dev dependency.
#[default]
NormalOrDev,
/// Build dependency or proc-macro.
HostDep,
/// Any dependency with both artifact and target specified.
///
/// That is, `dep = { …, artifact = <crate-type>, target = <triple> }`
ArtifactDep(CompileTarget),
}
impl std::fmt::Display for FeaturesFor {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
match self {
FeaturesFor::HostDep => f.write_str("host"),
FeaturesFor::ArtifactDep(target) => f.write_str(&target.rustc_target()),
FeaturesFor::NormalOrDev => Ok(()),
}
}
}
impl FeaturesFor {
pub fn from_for_host(for_host: bool) -> FeaturesFor {
if for_host {
FeaturesFor::HostDep
} else {
FeaturesFor::NormalOrDev
}
}
pub fn from_for_host_or_artifact_target(
for_host: bool,
artifact_target: Option<CompileTarget>,
) -> FeaturesFor {
match artifact_target {
Some(target) => FeaturesFor::ArtifactDep(target),
None => {
if for_host {
FeaturesFor::HostDep
} else {
FeaturesFor::NormalOrDev
}
}
}
}
fn apply_opts(self, opts: &FeatureOpts) -> Self {
if opts.decouple_host_deps {
self
} else {
FeaturesFor::default()
}
}
}
impl FeatureOpts {
pub fn new(
ws: &Workspace<'_>,
has_dev_units: HasDevUnits,
force_all_targets: ForceAllTargets,
) -> CargoResult<FeatureOpts> {
let mut opts = FeatureOpts::default();
let unstable_flags = ws.config().cli_unstable();
let mut enable = |feat_opts: &Vec<String>| {
for opt in feat_opts {
match opt.as_ref() {
"build_dep" | "host_dep" => opts.decouple_host_deps = true,
"dev_dep" => opts.decouple_dev_deps = true,
"itarget" => opts.ignore_inactive_targets = true,
"all" => {
opts.decouple_host_deps = true;
opts.decouple_dev_deps = true;
opts.ignore_inactive_targets = true;
}
"compare" => opts.compare = true,
"ws" => unimplemented!(),
s => bail!("-Zfeatures flag `{}` is not supported", s),
}
}
Ok(())
};
if let Some(feat_opts) = unstable_flags.features.as_ref() {
enable(feat_opts)?;
}
match ws.resolve_behavior() {
ResolveBehavior::V1 => {}
ResolveBehavior::V2 => {
enable(&vec!["all".to_string()]).unwrap();
}
}
if let HasDevUnits::Yes = has_dev_units {
// Dev deps cannot be decoupled when they are in use.
opts.decouple_dev_deps = false;
}
if let ForceAllTargets::Yes = force_all_targets {
opts.ignore_inactive_targets = false;
}
Ok(opts)
}
/// Creates a new FeatureOpts for the given behavior.
pub fn new_behavior(behavior: ResolveBehavior, has_dev_units: HasDevUnits) -> FeatureOpts {
match behavior {
ResolveBehavior::V1 => FeatureOpts::default(),
ResolveBehavior::V2 => FeatureOpts {
decouple_host_deps: true,
decouple_dev_deps: has_dev_units == HasDevUnits::No,
ignore_inactive_targets: true,
compare: false,
},
}
}
}
/// Features flags requested for a package.
///
/// This should be cheap and fast to clone, it is used in the resolver for
/// various caches.
///
/// This is split into enum variants because the resolver needs to handle
/// features coming from different places (command-line and dependency
/// declarations), but those different places have different constraints on
/// which syntax is allowed. This helps ensure that every place dealing with
/// features is properly handling those syntax restrictions.
#[derive(Debug, Clone, Eq, PartialEq, Hash)]
pub enum RequestedFeatures {
/// Features requested on the command-line with flags.
CliFeatures(CliFeatures),
/// Features specified in a dependency declaration.
DepFeatures {
/// The `features` dependency field.
features: FeaturesSet,
/// The `default-features` dependency field.
uses_default_features: bool,
},
}
/// Features specified on the command-line.
#[derive(Debug, Clone, Eq, PartialEq, Hash)]
pub struct CliFeatures {
/// Features from the `--features` flag.
pub features: Rc<BTreeSet<FeatureValue>>,
/// The `--all-features` flag.
pub all_features: bool,
/// Inverse of `--no-default-features` flag.
pub uses_default_features: bool,
}
impl CliFeatures {
/// Creates a new CliFeatures from the given command-line flags.
pub fn from_command_line(
features: &[String],
all_features: bool,
uses_default_features: bool,
) -> CargoResult<CliFeatures> {
let features = Rc::new(CliFeatures::split_features(features));
// Some early validation to ensure correct syntax.
for feature in features.iter() {
match feature {
// Maybe call validate_feature_name here once it is an error?
FeatureValue::Feature(_) => {}
FeatureValue::Dep { .. } => {
bail!(
"feature `{}` is not allowed to use explicit `dep:` syntax",
feature
);
}
FeatureValue::DepFeature { dep_feature, .. } => {
if dep_feature.contains('/') {
bail!("multiple slashes in feature `{}` is not allowed", feature);
}
}
}
}
Ok(CliFeatures {
features,
all_features,
uses_default_features,
})
}
/// Creates a new CliFeatures with the given `all_features` setting.
pub fn new_all(all_features: bool) -> CliFeatures {
CliFeatures {
features: Rc::new(BTreeSet::new()),
all_features,
uses_default_features: true,
}
}
fn split_features(features: &[String]) -> BTreeSet<FeatureValue> {
features
.iter()
.flat_map(|s| s.split_whitespace())
.flat_map(|s| s.split(','))
.filter(|s| !s.is_empty())
.map(InternedString::new)
.map(FeatureValue::new)
.collect()
}
}
impl ResolvedFeatures {
/// Returns the list of features that are enabled for the given package.
pub fn activated_features(
&self,
pkg_id: PackageId,
features_for: FeaturesFor,
) -> Vec<InternedString> {
self.activated_features_int(pkg_id, features_for)
.expect("activated_features for invalid package")
}
/// Returns if the given dependency should be included.
///
/// This handles dependencies disabled via `cfg` expressions and optional
/// dependencies which are not enabled.
pub fn is_dep_activated(
&self,
pkg_id: PackageId,
features_for: FeaturesFor,
dep_name: InternedString,
) -> bool {
let key = features_for.apply_opts(&self.opts);
self.activated_dependencies
.get(&(pkg_id, key))
.map(|deps| deps.contains(&dep_name))
.unwrap_or(false)
}
/// Variant of `activated_features` that returns `None` if this is
/// not a valid pkg_id/is_build combination. Used in places which do
/// not know which packages are activated (like `cargo clean`).
pub fn activated_features_unverified(
&self,
pkg_id: PackageId,
features_for: FeaturesFor,
) -> Option<Vec<InternedString>> {
self.activated_features_int(pkg_id, features_for).ok()
}
fn activated_features_int(
&self,
pkg_id: PackageId,
features_for: FeaturesFor,
) -> CargoResult<Vec<InternedString>> {
let fk = features_for.apply_opts(&self.opts);
if let Some(fs) = self.activated_features.get(&(pkg_id, fk)) {
Ok(fs.iter().cloned().collect())
} else {
bail!("features did not find {:?} {:?}", pkg_id, fk)
}
}
/// Compares the result against the original resolver behavior.
///
/// Used by `cargo fix --edition` to display any differences.
pub fn compare_legacy(&self, legacy: &ResolvedFeatures) -> DiffMap {
self.activated_features
.iter()
.filter_map(|((pkg_id, for_host), new_features)| {
let old_features = legacy
.activated_features
.get(&(*pkg_id, *for_host))
// The new features may have for_host entries where the old one does not.
.or_else(|| {
legacy
.activated_features
.get(&(*pkg_id, FeaturesFor::default()))
})
.map(|feats| feats.iter().cloned().collect())
.unwrap_or_else(|| BTreeSet::new());
// The new resolver should never add features.
assert_eq!(new_features.difference(&old_features).next(), None);
let removed_features: BTreeSet<_> =
old_features.difference(new_features).cloned().collect();
if removed_features.is_empty() {
None
} else {
Some(((*pkg_id, *for_host), removed_features))
}
})
.collect()
}
}
/// Map of differences.
///
/// Key is `(pkg_id, for_host)`. Value is a set of features or dependencies removed.
pub type DiffMap = BTreeMap<PackageFeaturesKey, BTreeSet<InternedString>>;
/// The new feature resolver that [`resolve`]s your project.
///
/// For more information, please see the [module-level documentation].
///
/// [`resolve`]: Self::resolve
/// [module-level documentation]: crate::core::resolver::features
pub struct FeatureResolver<'a, 'cfg> {
ws: &'a Workspace<'cfg>,
target_data: &'a mut RustcTargetData<'cfg>,
/// The platforms to build for, requested by the user.
requested_targets: &'a [CompileKind],
resolve: &'a Resolve,
package_set: &'a PackageSet<'cfg>,
/// Options that change how the feature resolver operates.
opts: FeatureOpts,
/// Map of features activated for each package.
activated_features: ActivateMap,
/// Map of optional dependencies activated for each package.
activated_dependencies: ActivateMap,
/// Keeps track of which packages have had its dependencies processed.
/// Used to avoid cycles, and to speed up processing.
processed_deps: HashSet<PackageFeaturesKey>,
/// If this is `true`, then a non-default `feature_key` needs to be tracked while
/// traversing the graph.
///
/// This is only here to avoid calling `is_proc_macro` when all feature
/// options are disabled (because `is_proc_macro` can trigger downloads).
/// This has to be separate from `FeatureOpts.decouple_host_deps` because
/// `for_host` tracking is also needed for `itarget` to work properly.
track_for_host: bool,
/// `dep_name?/feat_name` features that will be activated if `dep_name` is
/// ever activated.
///
/// The key is the `(package, for_host, dep_name)` of the package whose
/// dependency will trigger the addition of new features. The value is the
/// set of features to activate.
deferred_weak_dependencies:
HashMap<(PackageId, FeaturesFor, InternedString), HashSet<InternedString>>,
}
impl<'a, 'cfg> FeatureResolver<'a, 'cfg> {
/// Runs the resolution algorithm and returns a new [`ResolvedFeatures`]
/// with the result.
pub fn resolve(
ws: &Workspace<'cfg>,
target_data: &'a mut RustcTargetData<'cfg>,
resolve: &Resolve,
package_set: &'a PackageSet<'cfg>,
cli_features: &CliFeatures,
specs: &[PackageIdSpec],
requested_targets: &[CompileKind],
opts: FeatureOpts,
) -> CargoResult<ResolvedFeatures> {
use crate::util::profile;
let _p = profile::start("resolve features");
let track_for_host = opts.decouple_host_deps || opts.ignore_inactive_targets;
let mut r = FeatureResolver {
ws,
target_data,
requested_targets,
resolve,
package_set,
opts,
activated_features: HashMap::new(),
activated_dependencies: HashMap::new(),
processed_deps: HashSet::new(),
track_for_host,
deferred_weak_dependencies: HashMap::new(),
};
r.do_resolve(specs, cli_features)?;
tracing::debug!("features={:#?}", r.activated_features);
if r.opts.compare {
r.compare();
}
Ok(ResolvedFeatures {
activated_features: r.activated_features,
activated_dependencies: r.activated_dependencies,
opts: r.opts,
})
}
/// Performs the process of resolving all features for the resolve graph.
fn do_resolve(
&mut self,
specs: &[PackageIdSpec],
cli_features: &CliFeatures,
) -> CargoResult<()> {
let member_features = self.ws.members_with_features(specs, cli_features)?;
for (member, cli_features) in &member_features {
let fvs = self.fvs_from_requested(member.package_id(), cli_features);
let fk = if self.track_for_host && self.is_proc_macro(member.package_id()) {
// Also activate for normal dependencies. This is needed if the
// proc-macro includes other targets (like binaries or tests),
// or running in `cargo test`. Note that in a workspace, if
// the proc-macro is selected on the command like (like with
// `--workspace`), this forces feature unification with normal
// dependencies. This is part of the bigger problem where
// features depend on which packages are built.
self.activate_pkg(member.package_id(), FeaturesFor::default(), &fvs)?;
FeaturesFor::HostDep
} else {
FeaturesFor::default()
};
self.activate_pkg(member.package_id(), fk, &fvs)?;
}
Ok(())
}
/// Activates [`FeatureValue`]s on the given package.
///
/// This is the main entrance into the recursion of feature activation
/// for a package.
fn activate_pkg(
&mut self,
pkg_id: PackageId,
fk: FeaturesFor,
fvs: &[FeatureValue],
) -> CargoResult<()> {
tracing::trace!("activate_pkg {} {}", pkg_id.name(), fk);
// Add an empty entry to ensure everything is covered. This is intended for
// finding bugs where the resolver missed something it should have visited.
// Remove this in the future if `activated_features` uses an empty default.
self.activated_features
.entry((pkg_id, fk.apply_opts(&self.opts)))
.or_insert_with(BTreeSet::new);
for fv in fvs {
self.activate_fv(pkg_id, fk, fv)?;
}
if !self.processed_deps.insert((pkg_id, fk)) {
// Already processed dependencies. There's no need to process them
// again. This is primarily to avoid cycles, but also helps speed
// things up.
//
// This is safe because if another package comes along and adds a
// feature on this package, it will immediately add it (in
// `activate_fv`), and recurse as necessary right then and there.
// For example, consider we've already processed our dependencies,
// and another package comes along and enables one of our optional
// dependencies, it will do so immediately in the
// `FeatureValue::DepFeature` branch, and then immediately
// recurse into that optional dependency. This also holds true for
// features that enable other features.
return Ok(());
}
for (dep_pkg_id, deps) in self.deps(pkg_id, fk)? {
for (dep, dep_fk) in deps {
if dep.is_optional() {
// Optional dependencies are enabled in `activate_fv` when
// a feature enables it.
continue;
}
// Recurse into the dependency.
let fvs = self.fvs_from_dependency(dep_pkg_id, dep);
self.activate_pkg(dep_pkg_id, dep_fk, &fvs)?;
}
}
Ok(())
}
/// Activate a single FeatureValue for a package.
fn activate_fv(
&mut self,
pkg_id: PackageId,
fk: FeaturesFor,
fv: &FeatureValue,
) -> CargoResult<()> {
tracing::trace!("activate_fv {} {} {}", pkg_id.name(), fk, fv);
match fv {
FeatureValue::Feature(f) => {
self.activate_rec(pkg_id, fk, *f)?;
}
FeatureValue::Dep { dep_name } => {
self.activate_dependency(pkg_id, fk, *dep_name)?;
}
FeatureValue::DepFeature {
dep_name,
dep_feature,
weak,
} => {
self.activate_dep_feature(pkg_id, fk, *dep_name, *dep_feature, *weak)?;
}
}
Ok(())
}
/// Activate the given feature for the given package, and then recursively
/// activate any other features that feature enables.
fn activate_rec(
&mut self,
pkg_id: PackageId,
fk: FeaturesFor,
feature_to_enable: InternedString,
) -> CargoResult<()> {
tracing::trace!(
"activate_rec {} {} feat={}",
pkg_id.name(),
fk,
feature_to_enable
);
let enabled = self
.activated_features
.entry((pkg_id, fk.apply_opts(&self.opts)))
.or_insert_with(BTreeSet::new);
if !enabled.insert(feature_to_enable) {
// Already enabled.
return Ok(());
}
let summary = self.resolve.summary(pkg_id);
let feature_map = summary.features();
let Some(fvs) = feature_map.get(&feature_to_enable) else {
// TODO: this should only happen for optional dependencies.
// Other cases should be validated by Summary's `build_feature_map`.
// Figure out some way to validate this assumption.
tracing::debug!(
"pkg {:?} does not define feature {}",
pkg_id,
feature_to_enable
);
return Ok(());
};
for fv in fvs {
self.activate_fv(pkg_id, fk, fv)?;
}
Ok(())
}
/// Activate a dependency (`dep:dep_name` syntax).
fn activate_dependency(
&mut self,
pkg_id: PackageId,
fk: FeaturesFor,
dep_name: InternedString,
) -> CargoResult<()> {
// Mark this dependency as activated.
let save_decoupled = fk.apply_opts(&self.opts);
self.activated_dependencies
.entry((pkg_id, save_decoupled))
.or_default()
.insert(dep_name);
// Check for any deferred features.
let to_enable = self
.deferred_weak_dependencies
.remove(&(pkg_id, fk, dep_name));
// Activate the optional dep.
for (dep_pkg_id, deps) in self.deps(pkg_id, fk)? {
for (dep, dep_fk) in deps {
if dep.name_in_toml() != dep_name {
continue;
}
if let Some(to_enable) = &to_enable {
for dep_feature in to_enable {
tracing::trace!(
"activate deferred {} {} -> {}/{}",
pkg_id.name(),
fk,
dep_name,
dep_feature
);
let fv = FeatureValue::new(*dep_feature);
self.activate_fv(dep_pkg_id, dep_fk, &fv)?;
}
}
let fvs = self.fvs_from_dependency(dep_pkg_id, dep);
self.activate_pkg(dep_pkg_id, dep_fk, &fvs)?;
}
}
Ok(())
}
/// Activate a feature within a dependency (`dep_name/feat_name` syntax).
fn activate_dep_feature(
&mut self,
pkg_id: PackageId,
fk: FeaturesFor,
dep_name: InternedString,
dep_feature: InternedString,
weak: bool,
) -> CargoResult<()> {
for (dep_pkg_id, deps) in self.deps(pkg_id, fk)? {
for (dep, dep_fk) in deps {
if dep.name_in_toml() != dep_name {
continue;
}
if dep.is_optional() {
let save_for_host = fk.apply_opts(&self.opts);
if weak
&& !self
.activated_dependencies
.get(&(pkg_id, save_for_host))
.map(|deps| deps.contains(&dep_name))
.unwrap_or(false)
{
// This is weak, but not yet activated. Defer in case
// something comes along later and enables it.
tracing::trace!(
"deferring feature {} {} -> {}/{}",
pkg_id.name(),
fk,
dep_name,
dep_feature
);
self.deferred_weak_dependencies
.entry((pkg_id, fk, dep_name))
.or_default()
.insert(dep_feature);
continue;
}
// Activate the dependency on self.
let fv = FeatureValue::Dep { dep_name };
self.activate_fv(pkg_id, fk, &fv)?;
if !weak {
// The old behavior before weak dependencies were
// added is to also enables a feature of the same
// name.
//
// Don't enable if the implicit optional dependency
// feature wasn't created due to `dep:` hiding.
// See rust-lang/cargo#10788 and rust-lang/cargo#12130
let summary = self.resolve.summary(pkg_id);
let feature_map = summary.features();
if feature_map.contains_key(&dep_name) {
self.activate_rec(pkg_id, fk, dep_name)?;
}
}
}
// Activate the feature on the dependency.
let fv = FeatureValue::new(dep_feature);
self.activate_fv(dep_pkg_id, dep_fk, &fv)?;
}
}
Ok(())
}
/// Returns Vec of FeatureValues from a Dependency definition.
fn fvs_from_dependency(&self, dep_id: PackageId, dep: &Dependency) -> Vec<FeatureValue> {
let summary = self.resolve.summary(dep_id);
let feature_map = summary.features();
let mut result: Vec<FeatureValue> = dep
.features()
.iter()
.map(|f| FeatureValue::new(*f))
.collect();
let default = InternedString::new("default");
if dep.uses_default_features() && feature_map.contains_key(&default) {
result.push(FeatureValue::Feature(default));
}
result
}
/// Returns Vec of FeatureValues from a set of command-line features.
fn fvs_from_requested(
&self,
pkg_id: PackageId,
cli_features: &CliFeatures,
) -> Vec<FeatureValue> {
let summary = self.resolve.summary(pkg_id);
let feature_map = summary.features();
let mut result: Vec<FeatureValue> = cli_features.features.iter().cloned().collect();
let default = InternedString::new("default");
if cli_features.uses_default_features && feature_map.contains_key(&default) {
result.push(FeatureValue::Feature(default));
}
if cli_features.all_features {
result.extend(feature_map.keys().map(|k| FeatureValue::Feature(*k)))
}
result
}
/// Returns the dependencies for a package, filtering out inactive targets.
fn deps(
&mut self,
pkg_id: PackageId,
fk: FeaturesFor,
) -> CargoResult<Vec<(PackageId, Vec<(&'a Dependency, FeaturesFor)>)>> {
// Helper for determining if a platform is activated.
fn platform_activated(
dep: &Dependency,
fk: FeaturesFor,
target_data: &RustcTargetData<'_>,
requested_targets: &[CompileKind],
) -> bool {
// We always count platforms as activated if the target stems from an artifact
// dependency's target specification. This triggers in conjunction with
// `[target.'cfg(…)'.dependencies]` manifest sections.
match (dep.is_build(), fk) {
(true, _) | (_, FeaturesFor::HostDep) => {
// We always care about build-dependencies, and they are always
// Host. If we are computing dependencies "for a build script",
// even normal dependencies are host-only.
target_data.dep_platform_activated(dep, CompileKind::Host)
}
(_, FeaturesFor::NormalOrDev) => requested_targets
.iter()
.any(|kind| target_data.dep_platform_activated(dep, *kind)),
(_, FeaturesFor::ArtifactDep(target)) => {
target_data.dep_platform_activated(dep, CompileKind::Target(target))
}
}
}
self.resolve
.deps(pkg_id)
.map(|(dep_id, deps)| {
let deps = deps
.iter()
.filter(|dep| {
if dep.platform().is_some()
&& self.opts.ignore_inactive_targets
&& !platform_activated(
dep,
fk,
self.target_data,
self.requested_targets,
)
{
return false;
}
if self.opts.decouple_dev_deps && dep.kind() == DepKind::Development {
return false;
}
true
})
.collect_vec() // collect because the next closure mutably borrows `self.target_data`
.into_iter()
.map(|dep| {
// Each `dep`endency can be built for multiple targets. For one, it
// may be a library target which is built as initially configured
// by `fk`. If it appears as build dependency, it must be built
// for the host.
//
// It may also be an artifact dependency,
// which could be built either
//
// - for a specified (aka 'forced') target, specified by
// `dep = { …, target = <triple>` }`
// - as an artifact for use in build dependencies that should
// build for whichever `--target`s are specified
// - like a library would be built
//
// Generally, the logic for choosing a target for dependencies is
// unaltered and used to determine how to build non-artifacts,
// artifacts without target specification and no library,
// or an artifacts library.
//
// All this may result in a dependency being built multiple times
// for various targets which are either specified in the manifest
// or on the cargo command-line.
let lib_fk = if fk == FeaturesFor::default() {
(self.track_for_host && (dep.is_build() || self.is_proc_macro(dep_id)))
.then(|| FeaturesFor::HostDep)
.unwrap_or_default()
} else {
fk
};
// `artifact_target_keys` are produced to fulfil the needs of artifacts that have a target specification.
let artifact_target_keys = dep
.artifact()
.map(|artifact| {
let host_triple = self.target_data.rustc.host;
// not all targets may be queried before resolution since artifact dependencies
// and per-pkg-targets are not immediately known.
let mut activate_target = |target| {
let name = dep.name_in_toml();
self.target_data
.merge_compile_kind(CompileKind::Target(target))
.with_context(|| format!("failed to determine target information for target `{target}`.\n \
Artifact dependency `{name}` in package `{pkg_id}` requires building for `{target}`", target = target.rustc_target()))
};
CargoResult::Ok((
artifact.is_lib(),
artifact
.target()
.map(|target| {
CargoResult::Ok(match target {
ArtifactTarget::Force(target) => {
activate_target(target)?;
vec![FeaturesFor::ArtifactDep(target)]
}
// FIXME: this needs to interact with the `default-target` and `forced-target` values
// of the dependency
ArtifactTarget::BuildDependencyAssumeTarget => self
.requested_targets
.iter()
.map(|kind| match kind {
CompileKind::Host => {
CompileTarget::new(&host_triple)
.unwrap()
}
CompileKind::Target(target) => *target,
})
.map(|target| {
activate_target(target)?;
Ok(FeaturesFor::ArtifactDep(target))
})
.collect::<CargoResult<_>>()?,
})
})
.transpose()?,
))
})
.transpose()?;
let dep_fks = match artifact_target_keys {
// The artifact is also a library and does specify custom
// targets.
// The library's feature key needs to be used alongside
// the keys artifact targets.
Some((is_lib, Some(mut dep_fks))) if is_lib => {
dep_fks.push(lib_fk);
dep_fks
}
// The artifact is not a library, but does specify
// custom targets.
// Use only these targets feature keys.
Some((_, Some(dep_fks))) => dep_fks,
// There is no artifact in the current dependency
// or there is no target specified on the artifact.
// Use the standard feature key without any alteration.
Some((_, None)) | None => vec![lib_fk],
};
Ok(dep_fks.into_iter().map(move |dep_fk| (dep, dep_fk)))
})
.flatten_ok()
.collect::<CargoResult<Vec<_>>>()?;
Ok((dep_id, deps))
})
.filter(|res| res.as_ref().map_or(true, |(_id, deps)| !deps.is_empty()))
.collect()
}
/// Compare the activated features to the resolver. Used for testing.
fn compare(&self) {
let mut found = false;
for ((pkg_id, dep_kind), features) in &self.activated_features {
let r_features = self.resolve.features(*pkg_id);
if !r_features.iter().eq(features.iter()) {
crate::drop_eprintln!(
self.ws.config(),
"{}/{:?} features mismatch\nresolve: {:?}\nnew: {:?}\n",
pkg_id,
dep_kind,
r_features,
features
);
found = true;
}
}
if found {
panic!("feature mismatch");
}
}
fn is_proc_macro(&self, package_id: PackageId) -> bool {
self.package_set
.get_one(package_id)
.expect("packages downloaded")
.proc_macro()
}
}